As part of a continuing study of the cellular organization of the lamprey brain and spinal cord, the nervous control of respiration, eye movements, and swimming will be investigated during the coming year. Generator cells for respiratory discharges will be sought with intracellular recordings on the basis of spontaneous, periodic activity preceding that of gill motoneurons. Oculomotoneurons will be identified physiologically during intracellular recordings and morphologically with injections of HRP and Procion Yellow. Synaptic potentials will be recorded in oculomotoneurons after stimulation of the vestibular nerves. Application of L-DOPA to the isolated lamprey spinal cord produces phasic discharges of myotomal motoneurons like those of swimming. A search will be made for interneurons which are excited directly by the drug. BIBLIOGRAPHIC REFERENCES: Rovainen, C. M. (1976) Regeneration of Muller and Mauthner axons after spinal transection in larval lampreys. J. comp. Neurol. 168: 545-554. Rovainen, C. M. (1977) Neural control of ventilation in the lamprey. Fed. Proc. In press.